Hollow rivet and process for making same



Dec. 28, 1926. 1,611,942

L. M. PERSONS HOLLOW RIVET AND PROCESS FOR MAKING SAME Filed 001:. 20.1.920

Patented Dec. 28, 1926.

miwanncn iairnnsons, or corner, rumors, ASSIGNOB'TO coox nmc'rarc com-PANY, OI CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIE.

, HOLLOW BIVET AND YBOCESS FOR MAKING BAKE.

Application filed Qctober 20, 192). Serial No. 418,308.

' My invention relates to split tubular rivets and the roc'ess formaking. same.'

One 0 ject of my invention is the provision of a simple and eflicienttubular rivet capable of being easily expanded.

Another object of my invention is the provision of a tubular rivetinternally threaded and capable of being expanded by adjusting a screwslightly larger than the internal diameter of the rivet.

A further object is the provision of a tubular rivet formed of sheetmaterial having the threads formed by stamping serrations in the sheetmaterial before the latter is made into tubular form.

A still further object is the provision of a simple and efiicient methodof making rivets, such as above referred to. 7

Other objects will appear hereinafter.

An embodiment of my invention is shown in the accompanyin drawing,forming a part of this specification, and in Which Fig. 1 is aperspective view of a blank from which my tubular rivet is formed;

Fi 2 is a similar view of the blank having t e serrations formed thereinand the longitudinal edges bent up;

F i 3 is a similar view showing the tubular rivet completely formed;

Fig. 4 is an enlarged fragmental section of a motor core having atubular rivet therein embodying my invention;

Fig. 5 is a fragmental section, more or less diagrammatical,illustrating the method of forming my improved rivet; and

Fig. 6 is an elevation, more or less diagrammatical, illustrating thefinishing process of making my im roved rivet.

My improved rivet as the advantage that it can be made veryeconomically, much more so that where the tubular rivet must be madefrom a tube and internally threaded with dies.

In forming my rivet I first cutout a blank, such as indicated in Fig. 1,of the desired size to give a finished rivet in the size to be made. Thenext step in forming the rivet is to place it in the position indicatedin Fig. 5 at 7 in a forming die 8. The punch 9 is then brought down ontothe blank 7 pressing it from its dotted line position to its full lineosition shown in Fig. 5. The punch 9 an die 8 are so formed that theserrations 10, clearly indicated in Fig. 2, will be formed. At the sametime the die 8 and punch 9 will turn up the longitudinal edges 11 of theblank, as indicated in Fig. 2. The blank is next placed in a die, suchas indicated in Fig. 6, and upon members 12 of such dies being forced inthe directions of the arrows 13 the blank will be bent from itglfullline position to that indicated in dotte lines in said Fig. 6, thuscompleting the formation of the split tubular rivet with its internalthreads.

This rivet will be useful in many places and I find it particularlyadaptable for securing the laminations of motors, dynamos, and the like,together. In Fig. 4 I have indicated the usual core laminations 14 of amotor which are provided with registering perforations 15 therein forreceiving a rivet to secure such laminations together. With the 'use ofmy improved rivet the latter is placed in the perforations 15 and itsends riveted in the usual manner. After the rivet has been rivetedscrews 16 are passed through the cover members 17 of the usual motor, orthe like, constructions and threaded into the serrations 10 of myimproved rivet. In forming the serrations 10 it will be understood theyare to be made so that when finished the screw threads formed therebywill have the same pitch as the screws 16 to be used.

I preferably use screws 16 slightly larger than the internal diameter ofthe split rivets so that in forcing the screws into said rivets thelatter will be expanded into close contact with the walls ofperforations 15. The rough ed es 18 of the rivet will also tend to cutinto t e walls of the perforations 15 and facilitate holding the rivetagainst rotation while the screws 16 are being adjusted into or out ofposition.

In Fig. 4 I have indicated a screw 16 in each end of one of my improvedrivets. This expands both ends of the rivet and binds all of thelaminations together. One of the screws 16 holds the laminations 14 up1.

laminations, of a tubular rivet extending through registering openingstherein and having the ends thereof beaded, said rivet no illlaminations with registerin having one side longitudinally split topermit expansion thereof, frame members en-.

closing said laminations and screws threaded core having a perforationtherein, a tubularrivet in the perforation having beaded ends engagingthe surface of the outermost laminations, and a wedge member disposed inthe tubular rivet holding the latter in close contact with the walls ofsaid rforation. V 3. In combination, a plurality of core perforationstherein, a split tubular rivet 1n the perforations comprising acontinuous sheet metal plate having a smooth outer surface, and a screwthreaded in the tubular rivet adapted to expand the latter tightlyagainst the laminations.

4. In combination, a plurality of core laminations with registeringperforations therein, a split tubular rivet in said per- -tions togethercomprising riveting a split tubular rivet through the core laminationsand then expandin the tubular rivet into close contact. with t elaminations by forcing a wedge into the tubular rivet.

6. The method of locking core laminations together comprising riveting asplit tubular rivet through the laminations and then forcing a screwslightly larger than the internal diameter of the tubular rivet into thelatter for expanding such tubular rivet into close contact with thelaminations.

In testimony whereof I have signed my name to this specification on this28th day of September, A. D. 1920.

LAWRENCE M. PERSONS.

